A Study of Tarperprumig Safety and Effectiveness in Adults with Blood Vessel Inflammation Caused by ANCA Antibodies

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What is this study about?

This study is looking at Anti-Neutrophil Cytoplasmic Antibody (ANCA)-Associated Vasculitis, which is a condition where the body’s immune system mistakenly attacks blood vessels, causing inflammation and damage to various organs. The study includes two specific types of this condition: GPA (granulomatosis with polyangiitis) and MPA (microscopic polyangiitis). The treatment being tested is Tarperprumig, also known by its code name ALXN1820, which is given as an injection under the skin. Some participants will receive Tarperprumig while others will receive placebo. The purpose of this study is to evaluate the safety and tolerability of Tarperprumig in people with newly diagnosed or relapsing ANCA-associated vasculitis.

The study will involve participants who are between 18 and 80 years old and have either newly diagnosed or relapsing ANCA-associated vasculitis for which treatment with certain medications is being considered. Participants must have a positive test for specific antibodies called PR3-ANCA or MPO-ANCA and must meet certain disease activity requirements based on a scoring system called BVAS (Birmingham Vasculitis Activity Score). The study will monitor various safety measures including any unwanted effects of the treatment, changes in vital signs, physical examinations, laboratory tests, and heart function tests measured by ECG (electrocardiogram).

During the study, researchers will also look at how well the treatment works by checking if participants achieve disease remission, which means the disease becomes inactive, at different time points including week 26 and week 52. They will measure changes in kidney function using eGFR (estimated glomerular filtration rate), which shows how well the kidneys are filtering waste from the blood. Other measurements will include checking for protein in the urine using tests called UPCR (urine protein-to-creatinine ratio) and UACR (urine albumin-to-creatinine ratio), as well as looking for blood in the urine. The study will also track any disease damage over time using the Vasculitis Damage Index and monitor whether the disease comes back after achieving remission. The study is expected to run for approximately 52 weeks for each participant.

1 Initial treatment period with study medication

After joining the study, you will receive either tarperprumig or a placebo. A placebo is an inactive substance that looks like the real medication but contains no active ingredient.

The medication will be administered as an injection under the skin (subcutaneous injection).

You will receive this treatment alongside standard therapy, which may include rituximab or cyclophosphamide, medications commonly used to treat your condition.

The study is designed so that neither you nor your doctor will know whether you are receiving the active medication or placebo during the treatment period.

2 Regular monitoring and assessments

Throughout the study, your health will be monitored through various assessments.

Your doctor will check your vital signs, which include blood pressure, heart rate, and temperature.

You will undergo physical examinations to assess your overall health.

Regular blood tests and urine tests will be performed to monitor your kidney function and disease activity.

An electrocardiogram (ECG) will be performed to check your heart’s electrical activity.

Your disease activity will be assessed using a scoring system called BVAS (Birmingham Vasculitis Activity Score), which measures the severity of your vasculitis symptoms.

3 Week 26 evaluation

At week 26 (approximately 6 months after starting), your doctor will evaluate whether your disease is in remission. Remission means that your disease symptoms have significantly improved or disappeared.

Your kidney function will be assessed by measuring your estimated glomerular filtration rate (eGFR), which indicates how well your kidneys are filtering waste from your blood.

Tests will measure the amount of protein in your urine using ratios called UPCR and UACR, which help assess kidney damage.

The presence of blood in your urine (hematuria) will be measured by counting red blood cells.

Your doctor will assess any damage caused by the disease using the Vasculitis Damage Index (VDI).

4 Continued treatment and monitoring through week 52

Treatment and monitoring will continue until week 52 (approximately 1 year).

Regular assessments will continue throughout this period to track your disease activity and response to treatment.

Your doctor will monitor whether you maintain remission or experience a relapse, which means the disease becomes active again after improvement.

If you achieve remission, your doctor will track how long you maintain this improvement, referred to as sustained remission.

The same tests performed at week 26 will be repeated at week 52, including kidney function tests, urine protein measurements, and disease activity scores.

5 Safety monitoring throughout the study

Throughout the entire study period, any side effects or health problems you experience will be carefully recorded and monitored.

These are called treatment-emergent adverse events (TEAEs), which are any medical problems that occur after starting the study medication.

Serious health problems, called treatment-emergent serious adverse events (TESAEs), will be closely monitored and reported.

All changes in your health status compared to your condition at the beginning of the study will be documented.

Who Can Join the Study?

You must be between 18 and 80 years old at the time you agree to join the study
You must have newly diagnosed or returning ANCA-associated vasculitis, which is a condition where your immune system attacks your blood vessels. This includes specific types called GPA or MPA
Your doctor must consider that treatment with medications called rituximab or cyclophosphamide is appropriate for you
You must have a positive test for specific antibodies called PR3-ANCA or MPO-ANCA, either during the screening process or in the past. These are proteins in your blood that help diagnose your condition
You must have at least one major sign of active disease, or at least 3 minor signs, or at least 2 kidney-related signs according to a disease activity measurement called BVAS
Your kidney function must show an estimated glomerular filtration rate of at least 15, which is a measure of how well your kidneys are filtering waste from your blood
There is no weight requirement for this study
If you are a man, you must agree to use a condom during sexual activity and not donate sperm during the study and for a specified time after the last dose of the study medication
If you are a man, your partner who can become pregnant should also use highly effective birth control
If you are a woman who can become pregnant, you must use a highly effective birth control method with less than 1% failure rate during the study and for a specified time after the last dose
If you are a woman who can become pregnant, you must have a negative pregnancy test within 24 hours before receiving the first dose of study medication
If you are a woman, you must not be pregnant or breastfeeding
If you are a woman who can become pregnant, you must agree not to donate eggs during the study and for a specified time after the last dose
You must be willing and able to provide written consent to participate in the study
You must be able to follow all the requirements of the study

Who Cannot Join the Study?

The study information provided does not list specific reasons why patients cannot participate in this clinical trial
If you are interested in participating, the research team will review your complete medical history to determine if you meet all requirements for the study
General factors that often prevent participation in clinical trials may include having other serious medical conditions, taking certain medications, being pregnant or breastfeeding, or having allergies to study medications
The final decision about your eligibility will be made by the study doctors after a thorough medical evaluation

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country
Hospital Universitario De Navarra	Pamplona	Spain
Universitaetsmedizin Goettingen	Goettingen	Germany
Oncopole Claudius Regaud	Toulouse	France

Other Sites

Site Name	City	Country
Klinikum der Stadt Ludwigshafen am Rhein gGmbH	Ludwigshafen Am Rhein	Germany
Hospital Universitario Infanta Sofía	San Sebastian De Los Reyes	Spain
Azienda Ospedaliera di Padova	Padua	Italy
Virgen del Rocío University Hospital	Sevilla	Spain
Fondazione IRCCS Policlinico San Matteo	Pavia	Italy
Hospital Clinic De Barcelona	Barcelona	Spain
Charite Universitaetsmedizin Berlin KöR	Berlin	Germany
Wojskowy Instytut Medyczny Panstwowy Instytut Badawczy	Warsaw	Poland
Universita’ Di Pisa	Pisa	Italy
Samodzielny Publiczny Zaklad Opieki Zdrowotnej Szpital Uniwersytecki W Krakowie	Cracow	Poland
Uniwersytecki Szpital Kliniczny W Poznaniu	Poznan	Poland
Hopital Beaujon	Clichy	France
Universita Degli Studi Di Brescia	Brescia	Italy
Uwhzcdmyfvlwbumlujjdx Ekolw Avl	Essen	Germany
Hbadbrut Uwwrnyqegisdg Mtxsbjh Dl Vjdiijuorj	Santander	Spain
Apqxzuqdex Pyjtjqbx Hzaocoyp Dy Mfztrmrxt	Marseille	France
Knyswdyg dcr Ufyhrxtmyhix Muxujatt Alc	Munich	Germany
Uyhqxsufzbgnrh Cvrevie Keracxqfj	Gdansk	Poland
Hocsqcof Uejkamdrpdbmyu Scscnevdis &wmntww Hlsdxty dk Hqhnrlkbbmu	STRASBOURG, Alsace	France

Trial status

Country	Status	Recruitment Start
France	Recruiting	01.11.2025
Germany	Recruiting	01.11.2025
Italy	Recruiting	01.11.2025
Poland	Recruiting	01.11.2025
Spain	Recruiting	01.11.2025

Trial locations

Tarperprumig is an investigational medication being tested in this clinical trial for people with a condition that causes inflammation of blood vessels. This medication is being studied to see if it is safe and effective in treating adults with this type of vasculitis.

Placebo is an inactive substance that looks like the real medication but contains no active treatment. It is used in this study to compare the effects of tarperprumig against no active treatment, helping researchers understand if the medication truly works.

Investigated diseases:

Anti-neutrophil cytoplasmic antibody positive vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis – This is a group of rare autoimmune diseases where the body’s immune system mistakenly attacks small and medium-sized blood vessels throughout the body. The condition occurs when abnormal antibodies called ANCA cause inflammation and damage to the walls of blood vessels. This inflammation can affect various organs including the kidneys, lungs, skin, joints, and nervous system. The disease can appear suddenly as a new diagnosis or can return after a period of improvement, which is called relapsing. As the condition progresses, it may cause reduced kidney function, protein in the urine, blood in the urine, and damage to affected organs. The severity of symptoms varies depending on which blood vessels and organs are involved in the inflammatory process.

Trial ID:

2025-521706-17-00

Protocol code:

ALXN1820-ANCA-201

Trial Phase:

Therapeutic exploratory (Phase II)

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A Study of Tarperprumig Safety and Effectiveness in Adults with Blood Vessel Inflammation Caused by ANCA Antibodies

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